That tied Oklahoma State coach Eddie Sutton with Syracuse's Jim Boeheim for 10th place on the NCAA's all-time list for tournament victories. Sutton is 29-17 and Boeheim, who lost in the opening round for only the third time in 19 appearances, slipped to 29-19.

Peterson, who matched his career-high with five 3-pointers, hit his first two shots behind the arc to put his team ahead 6-0 and the Cowboys went on to lead by as many as nine in the first half. For the game, he hit 5-of-8 from behind the arc.

"I was just running, trying to find an open spot. I just kind of felt it," said Peterson, who is second on the Cowboys' all-time list for 3-pointers. "I caught it, it went down and my confidence went up."

Syracuse (21-12) started cold, hitting just five of its first 19 attempts from the field. The Orangemen were able to stay in the game with the help of 12 Oklahoma State turnovers in the first half and trailed 33-30 at the break.

Syracuse, hurt by cold shooting from the free-throw line late in the game, caught the Cowboys only once at 57-57.

Joe Adkins hit a 3-pointer to put the Cowboys (27-14) ahead to stay.

Joe Adkins takes a tumble, but Oklahoma State lands on its feet. (AP)

"We couldn't get a stop until we finally got a little run to tie it up at 57. Then Atkins stepped up and made a huge shot," Boeheim said.

Etan Thomas, who led the Orangemen with 21 points, missed three of five attempts from the foul line in the final 3:32 and the Orangemen missed their last four shots from the field in the final minute. For the game, Syracuse shot 59 percent from the free throw line.

"They tried to go to Thomas every time," Sutton said. "They tried to jam it in. We tried to double down and give support to whoever was covering him."

Oklahoma State, meanwhile, shot 73 percent from the free throw line and hit five of six foul shots in the final 45 seconds. Glenn Alexander hit two with 45 seconds left to give Oklahoma State a 66-60 lead. After Jason Hart and Ryan Blackwell missed 3-point attempts for Syracuse, Mason hit both ends of a bonus opportunity to put his team up 68-61 with 22 seconds remaining.

"I told them Syracuse is good and when you get down to the end, you don't want to beat yourself. You have to play with poise," Sutton said.

Oklahoma State was 8-of-18 from 3-point range.

"They got most of the treys against us in man-to-man (defense), which shouldn't have happened," Boeheim said.

The Orangemen switched to a zone late in the game, but Oklahoma State was able to get the ball inside, with Doug Gottlieb accumulating 11 assists.

"In the second half our guys found the hole well, and if they find the hole, I'm going to get them the ball," said Gottlieb, who has become the Cowboys' career leader in assists in just two seasons after transferring following his freshman year at Notre Dame.